Tag: physics

Questions Related to physics

An antenna serves the following purpose : 

physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

  1. Converts AF wave to RF wave

  2. Converts RF signal into electromagnetic energy

  3. Converts the guided EM waves into free space EM waves and vice versa

  4. Superimposes AF wave on RF wave

Show answer
Correct Option: C
Explanation:

The antenna serves as the region of transition between guided and free space propagation.

The concepts of communication are
a) mode of communication
b) need for modulation
c) types of modulation
d) detection of modulated wave

physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

  1. a, b, c are true

  2. b, c, d are true

  3. c, d, a are true

  4. a, b, c & d are true

Show answer
Correct Option: D
Explanation:

In the concept of communication,

(a) Modes of communication are video, audio, face-to-face and text transmission.
(b) Modulation is needed, because original signal doesn't have the power to reach the desired destination, so it is modulated.
(c) Modulation are of different types, as amplitude modulation, frequency modulation and phase modulation etc. 
(d) Detection of modulated wave is done to extract the original signal from modulated wave.

Buffer amplifier is used at the transmitting end to

physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

  1. feed carrier frequency to master oscillator

  2. amplify carrier frequency

  3. mix modulating signal with carrier frequency

  4. isolate master oscillator from other stages of transmitter.

Show answer
Correct Option: D
Explanation:

Displacement current is set up in a region where the electric field is changing with time.

The science of communication involving long distances is known as

physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

  1. mass-communication

  2. distant-communication

  3. tele-communication

  4. trans-communication

Show answer
Correct Option: C
Explanation:
Telecommunication is the transmission of signs, signals, messages, writings, images and sounds or intelligence of any nature by wire, radio, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology. 
 It is transmitted either electrically over physical media, such as cables, or via electromagnetic radiations.
20th and 21st century technologies for long-distance communication usually involve electrical and electromagnetic technologies, such as telegraph, telephone, and  radio, fiber optics, and communication satellites.

The useful message that is conveyed during communication is known as

physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

  1. text

  2. electric signal

  3. bytes

  4. information

Show answer
Correct Option: D
Explanation:

Out of the total message, usually a part is conveyed. This part of message is in form of bits called information.

The term channel is used to indicate

physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

  1. the amplitude range allocated to a given source

  2. the frequency range allocated to a given source

  3. the voltage-range allocated to a given source

  4. all of the above

Show answer
Correct Option: B
Explanation:

Channel represents the different frequency ranges over with radio frequencies exist. A change in channel for device would mean a change in range of frequency over which the device is being operated.

Consider telecommunication through optical fibres. Which of the following statement is not true?

physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

  1. Optical fibres may have homogenous core with a suitable cladding.

  2. Optical fibres can be graded refractive index.

  3. Optical fibres are subject to electromagnetic interference from outside.

  4. Optical fibres have extremely low transmission loss.

Show answer
Correct Option: C
Explanation:

Optical fibres are not subjected to electro-magnetic interference from outside.

Without which of the following a generalized block diagram of communication system is incomplete?

physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

  1. Channel

  2. Receiver

  3. Transmitter

  4. All of the above

Show answer
Correct Option: D
Explanation:

Transmitter - which converts the signal in an electrical signal and then sends it.

Channel - which carries the signal.
Receiver - which receives and converts the signal in original form.

These three are essential  for a communication system.

What are the three essential part of a communication system?

physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

  1. transmitter, channel and receiver

  2. transmitter, information source and receiver

  3. information source ,transmitter and channel

  4. transmitter , noise and channel

Show answer
Correct Option: A
Explanation:

Transmitter- which converts the signal in an electrical signal and then send it. Channel - which carries the signal.

Receiver - which receives and converts the signal in original form.
These three are essential  for a communication system.

Which of the following is/are the example(s) of  real life telecommunication system?

physics communication system elements of a communication system elements of communication system electromagnetic waves and communication system

  1. Optical fiber communication

  2. Microwave communication

  3. Coaxial cable communication

  4. None of the above

Show answer
Correct Option: A,B,C
Explanation:

Optical Fiber Communication, Microwave communication, and  coaxial cable communication are all being used in real life as communication systems. These are the advanced systems with high information transfer rate.